diff --git a/.github/workflows/dependabot-pr.yml b/.github/workflows/dependabot-pr.yml
index 29d65609..272ebc81 100644
--- a/.github/workflows/dependabot-pr.yml
+++ b/.github/workflows/dependabot-pr.yml
@@ -25,7 +25,7 @@ jobs:
           ref: ${{ github.event.pull_request.head.ref }} # Check out the head of the actual branch, not the PR
           fetch-depth: 0 # otherwise, you will fail to push refs to dest repo
           token: ${{ secrets.DEPENDABOT_WORKFLOW_TOKEN }}
-      - uses: pyiron/actions/update-env-files@actions-4.0.13
+      - uses: pyiron/actions/update-env-files@main
       - name: UpdateDependabotPR commit
         run: |
           git config --local user.email "pyiron@mpie.de"
diff --git a/.github/workflows/hatch-release.yml b/.github/workflows/hatch-release.yml
index e1af3886..c6eb9d36 100644
--- a/.github/workflows/hatch-release.yml
+++ b/.github/workflows/hatch-release.yml
@@ -106,11 +106,11 @@ jobs:
     - name: Install npm dependencies
       if: inputs.use-node
       run: npm install
-    - uses: pyiron/actions/cached-miniforge@actions-4.0.13
+    - uses: pyiron/actions/cached-miniforge@main
       with:
         python-version: ${{ inputs.python-version }}
         env-files: ${{ inputs.env-files }}
-    - uses: pyiron/actions/update-pyproject-dependencies@actions-4.0.13
+    - uses: pyiron/actions/update-pyproject-dependencies@main
       with:
         input-toml: ${{ inputs.input-toml }}
         lower-bound-yaml: ${{ inputs.lower-bound-yaml }}
diff --git a/.github/workflows/pr-labeled.yml b/.github/workflows/pr-labeled.yml
index f86b78e0..6ae134d9 100644
--- a/.github/workflows/pr-labeled.yml
+++ b/.github/workflows/pr-labeled.yml
@@ -48,10 +48,10 @@ jobs:
 
   tests-and-coverage:
     if: contains(github.event.pull_request.labels.*.name, 'run_coverage')
-    uses: pyiron/actions/.github/workflows/tests-and-coverage.yml@actions-4.0.13
+    uses: pyiron/actions/.github/workflows/tests-and-coverage.yml@main
     secrets: inherit
 
   code-ql:
     if: contains(github.event.pull_request.labels.*.name, 'run_CodeQL')
-    uses: pyiron/actions/.github/workflows/codeql.yml@actions-4.0.13
+    uses: pyiron/actions/.github/workflows/codeql.yml@main
     secrets: inherit
diff --git a/.github/workflows/push-pull.yml b/.github/workflows/push-pull.yml
index 1cdb5064..3998fe57 100644
--- a/.github/workflows/push-pull.yml
+++ b/.github/workflows/push-pull.yml
@@ -96,6 +96,11 @@ on:
         description: 'An optional path to a file containing the names of notebooks to NOT build'
         default: .ci_support/exclude
         required: false
+      notebooks-secret-env-map:
+        type: string
+        description: 'Optional newline-separated SECRET_NAME or ENV_NAME=SECRET_NAME entries to export for notebook execution'
+        default: ''
+        required: false
       tests-env-files:
         type: string
         description: 'Paths to an arbitrary number of (space-separated) conda environment yaml files'
@@ -212,11 +217,11 @@ jobs:
           ref: ${{ github.event.pull_request.head.ref }} # Check out the head of the actual branch, not the PR
           fetch-depth: 0 # otherwise, you will fail to push refs to dest repo
         if: ${{ inputs.do-commit-updated-env }}
-      - uses: pyiron/actions/write-docs-env@actions-4.0.13
+      - uses: pyiron/actions/write-docs-env@main
         with:
           env-files: ${{ inputs.docs-env-files }}
         if: ${{ inputs.do-commit-updated-env }}
-      - uses: pyiron/actions/write-environment@actions-4.0.13
+      - uses: pyiron/actions/write-environment@main
         with:
           env-files: ${{ inputs.notebooks-env-files }}
           output-env-file: .binder/environment.yml
@@ -243,11 +248,11 @@ jobs:
     runs-on: ${{ inputs.runner }}
     steps:
       - uses: actions/checkout@v4
-      - uses: pyiron/actions/add-to-python-path@actions-4.0.13
+      - uses: pyiron/actions/add-to-python-path@main
         if: inputs.extra-python-paths != ''
         with:
           path-dirs: ${{ inputs.extra-python-paths }}
-      - uses: pyiron/actions/build-docs@actions-4.0.13
+      - uses: pyiron/actions/build-docs@main
         with:
           python-version: ${{ inputs.python-version }}
           env-files: ${{ inputs.docs-env-files }}
@@ -258,11 +263,17 @@ jobs:
     runs-on: ${{ inputs.runner }}
     steps:
       - uses: actions/checkout@v4
-      - uses: pyiron/actions/add-to-python-path@actions-4.0.13
+      - uses: pyiron/actions/add-to-python-path@main
         if: inputs.extra-python-paths != ''
         with:
           path-dirs: ${{ inputs.extra-python-paths }}
-      - uses: pyiron/actions/build-notebooks@actions-4.0.13
+      - uses: pyiron/actions/export-secret-env@main
+        if: ${{ inputs.notebooks-secret-env-map != '' }}
+        env:
+          PYIRON_ALL_SECRETS_JSON: ${{ toJSON(secrets) }}
+        with:
+          secret-env-map: ${{ inputs.notebooks-secret-env-map }}
+      - uses: pyiron/actions/build-notebooks@main
         with:
           python-version: ${{ inputs.python-version }}
           env-files: ${{ inputs.notebooks-env-files }}
@@ -299,11 +310,11 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - uses: pyiron/actions/add-to-python-path@actions-4.0.13
+    - uses: pyiron/actions/add-to-python-path@main
       if: inputs.extra-python-paths != ''
       with:
         path-dirs: ${{ inputs.extra-python-paths }}
-    - uses: pyiron/actions/unit-tests@actions-4.0.13
+    - uses: pyiron/actions/unit-tests@main
       with:
         python-version: ${{ matrix.python-version }}
         env-files: ${{ inputs.tests-env-files }}
@@ -316,7 +327,7 @@ jobs:
   coverage:
     needs: commit-updated-env
     if: ${{ inputs.do-codecov || inputs.do-coveralls || inputs.do-codacy }}
-    uses: pyiron/actions/.github/workflows/tests-and-coverage.yml@actions-4.0.13
+    uses: pyiron/actions/.github/workflows/tests-and-coverage.yml@main
     secrets: inherit
     with:
       tests-env-files: ${{ inputs.tests-env-files }}
@@ -336,11 +347,11 @@ jobs:
     runs-on: ${{ inputs.runner }}
     steps:
     - uses: actions/checkout@v4
-    - uses: pyiron/actions/add-to-python-path@actions-4.0.13
+    - uses: pyiron/actions/add-to-python-path@main
       if: inputs.extra-python-paths != ''
       with:
         path-dirs: ${{ inputs.extra-python-paths }}
-    - uses: pyiron/actions/unit-tests@actions-4.0.13
+    - uses: pyiron/actions/unit-tests@main
       with:
         python-version: ${{ inputs.python-version }}
         env-files: ${{ inputs.tests-env-files }}
@@ -355,11 +366,11 @@ jobs:
     runs-on: ${{ inputs.runner }}
     steps:
     - uses: actions/checkout@v4
-    - uses: pyiron/actions/add-to-python-path@actions-4.0.13
+    - uses: pyiron/actions/add-to-python-path@main
       if: inputs.extra-python-paths != ''
       with:
         path-dirs: ${{ inputs.extra-python-paths }}
-    - uses: pyiron/actions/unit-tests@actions-4.0.13
+    - uses: pyiron/actions/unit-tests@main
       with:
         python-version: ${{ inputs.alternate-tests-python-version }}
         env-files: ${{ inputs.alternate-tests-env-files }}
@@ -375,7 +386,7 @@ jobs:
     runs-on: ${{ inputs.runner }}
     steps:
       - uses: actions/checkout@v4
-      - uses: pyiron/actions/pip-check@actions-4.0.13
+      - uses: pyiron/actions/pip-check@main
         with:
           python-version: ${{ inputs.python-version }}
 
@@ -430,7 +441,7 @@ jobs:
           python-version: ${{ inputs.python-version }}
           architecture: x64
       - if: ${{ inputs.mypy-env-files != '' }}
-        uses: pyiron/actions/cached-miniforge@actions-4.0.13
+        uses: pyiron/actions/cached-miniforge@main
         with:
           python-version: ${{ inputs.python-version }}
           env-files: ${{ inputs.mypy-env-files }}
diff --git a/.github/workflows/pyproject-release.yml b/.github/workflows/pyproject-release.yml
index ece5f322..72703e5d 100644
--- a/.github/workflows/pyproject-release.yml
+++ b/.github/workflows/pyproject-release.yml
@@ -83,11 +83,11 @@ jobs:
     runs-on: ${{ inputs.runner }}
     steps:
     - uses: actions/checkout@v4
-    - uses: pyiron/actions/cached-miniforge@actions-4.0.13
+    - uses: pyiron/actions/cached-miniforge@main
       with:
         python-version: ${{ inputs.python-version }}
         env-files: ${{ inputs.env-files }}
-    - uses: pyiron/actions/update-pyproject-dependencies@actions-4.0.13
+    - uses: pyiron/actions/update-pyproject-dependencies@main
       with:
         input-toml: ${{ inputs.input-toml }}
         lower-bound-yaml: ${{ inputs.lower-bound-yaml }}
diff --git a/.github/workflows/tests-and-coverage.yml b/.github/workflows/tests-and-coverage.yml
index fa277002..b95fa3f4 100644
--- a/.github/workflows/tests-and-coverage.yml
+++ b/.github/workflows/tests-and-coverage.yml
@@ -69,11 +69,11 @@ jobs:
     runs-on: ${{ inputs.runner }}
     steps:
       - uses: actions/checkout@v4
-      - uses: pyiron/actions/add-to-python-path@actions-4.0.13
+      - uses: pyiron/actions/add-to-python-path@main
         if: inputs.extra-python-paths != ''
         with:
           path-dirs: ${{ inputs.extra-python-paths }}
-      - uses: pyiron/actions/unit-tests@actions-4.0.13
+      - uses: pyiron/actions/unit-tests@main
         with:
           python-version: ${{ inputs.python-version }}
           env-files: ${{ inputs.tests-env-files }}
diff --git a/.gitignore b/.gitignore
index 5aeb0fff..848f1a94 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,6 @@
 *.pyc
 .DS_Store
 .idea/
+.dir-locals.el
+.codex
+.codex/
\ No newline at end of file
diff --git a/.support/export_secret_env.py b/.support/export_secret_env.py
new file mode 100644
index 00000000..0d61996e
--- /dev/null
+++ b/.support/export_secret_env.py
@@ -0,0 +1,120 @@
+"""Export selected GitHub Actions secrets into later-step environment variables."""
+
+from __future__ import annotations
+
+import json
+import os
+import re
+import sys
+import uuid
+
+NAME_PATTERN = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")
+
+
+def workflow_escape(value: str) -> str:
+    """Escape text embedded in a GitHub workflow command."""
+    return value.replace("%", "%25").replace("\r", "%0D").replace("\n", "%0A")
+
+
+def fail(message: str) -> None:
+    print(f"::error::{workflow_escape(message)}", file=sys.stderr)
+    raise SystemExit(1)
+
+
+def parse_secret_env_map(raw_map: str) -> dict[str, str]:
+    """Parse mapping lines into environment-name to secret-name pairs."""
+    env_to_secret_name: dict[str, str] = {}
+
+    for line_number, raw_line in enumerate(raw_map.splitlines(), start=1):
+        line = raw_line.strip()
+        if not line or line.startswith("#"):
+            continue
+
+        if "=" in line:
+            env_name, secret_name = (part.strip() for part in line.split("=", 1))
+        else:
+            env_name = secret_name = line
+
+        if not env_name or not secret_name:
+            fail(f"Invalid secret env mapping on line {line_number}.")
+        if not NAME_PATTERN.fullmatch(env_name):
+            fail(
+                f"Invalid environment variable name {env_name!r} on line {line_number}."
+            )
+        if not NAME_PATTERN.fullmatch(secret_name):
+            fail(f"Invalid secret name {secret_name!r} on line {line_number}.")
+        if env_name in env_to_secret_name:
+            fail(f"Duplicate environment variable mapping for {env_name!r}.")
+
+        env_to_secret_name[env_name] = secret_name
+
+    return env_to_secret_name
+
+
+def load_secrets() -> dict[str, str]:
+    """Load the full secret object supplied only to the trusted export step."""
+    raw_secrets = os.environ.get("PYIRON_ALL_SECRETS_JSON")
+    if not raw_secrets:
+        fail("PYIRON_ALL_SECRETS_JSON is required when exporting selected secrets.")
+
+    try:
+        secrets = json.loads(raw_secrets)
+    except json.JSONDecodeError as exc:
+        fail(f"Failed to parse PYIRON_ALL_SECRETS_JSON: {exc}")
+
+    if not isinstance(secrets, dict):
+        fail("PYIRON_ALL_SECRETS_JSON must decode to a JSON object.")
+
+    return {str(name): str(value) for name, value in secrets.items()}
+
+
+def choose_github_env_delimiter(value: str) -> str:
+    """Choose a delimiter that is not present as a complete value line."""
+    value_lines = set(value.splitlines())
+    while True:
+        delimiter = f"PYIRON_SECRET_{uuid.uuid4().hex}"
+        if delimiter not in value_lines:
+            return delimiter
+
+
+def append_github_env(env_name: str, value: str) -> None:
+    """Append one environment variable using GitHub's multiline-safe format."""
+    github_env = os.environ.get("GITHUB_ENV")
+    if not github_env:
+        fail("GITHUB_ENV is not set.")
+
+    delimiter = choose_github_env_delimiter(value)
+    with open(github_env, "a", encoding="utf-8") as env_file:
+        env_file.write(f"{env_name}<<{delimiter}\n{value}\n{delimiter}\n")
+
+
+def main() -> int:
+    env_to_secret_name = parse_secret_env_map(
+        os.environ.get("PYIRON_SECRET_ENV_MAP", "")
+    )
+    if not env_to_secret_name:
+        return 0
+
+    secrets = load_secrets()
+    missing = [
+        secret_name
+        for secret_name in env_to_secret_name.values()
+        if secret_name not in secrets
+    ]
+    if missing:
+        fail("Requested secret(s) are not available: " + ", ".join(sorted(missing)))
+
+    for env_name, secret_name in env_to_secret_name.items():
+        value = secrets[secret_name]
+        if value:
+            print(f"::add-mask::{workflow_escape(value)}")
+        append_github_env(env_name, value)
+
+    print(
+        f"Exported {len(env_to_secret_name)} selected secret environment variable(s)."
+    )
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/README.md b/README.md
index 3701e540..be6dbd19 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,26 @@ Notebooks are found in all sub directories of `/notebooks`.  The files listed in
 
 A wrapper combining `conda-incubator/setup-miniconda` and `actions/cache` along with our own `write-environment` that allows you to easily make a cached conda environment from any number (>=1) of conda environment yaml files.
 
+### `export-secret-env`
+
+Exports a selected set of GitHub Actions secrets to the `$GITHUB_ENV` file so they are available in later steps of the same job.
+
+The `secret-env-map` input accepts newline-separated entries as either `SECRET_NAME` or `ENV_NAME=SECRET_NAME`.
+This is intended for reusable workflows that receive inherited secrets, but only want to pass an explicit allowlist onward to runtime code such as notebook execution.
+
+The action needs the available secrets as JSON via `PYIRON_ALL_SECRETS_JSON`.
+A minimal use looks like:
+
+```yaml
+- uses: pyiron/actions/export-secret-env@main
+  env:
+    PYIRON_ALL_SECRETS_JSON: ${{ toJSON(secrets) }}
+  with:
+    secret-env-map: |
+      SECRET_NAME
+      ENV_VAR_NAME=SECRET_NAME
+```
+
 ### `pip-check`
 
 Builds your environment with the `cached-minforge` action and then runs `pip check`.
@@ -119,7 +139,7 @@ on:
 
 jobs:
   pyiron:
-    uses: pyiron/actions/.github/workflows/push-pull.yml@actions-4.0.13
+    uses: pyiron/actions/.github/workflows/push-pull.yml@main
     secrets: inherit
 ```
 
diff --git a/build-docs/action.yml b/build-docs/action.yml
index ff82744d..0339b7cc 100644
--- a/build-docs/action.yml
+++ b/build-docs/action.yml
@@ -21,11 +21,11 @@ inputs:
 runs:
   using: 'composite'
   steps:
-  - uses: pyiron/actions/cached-miniforge@actions-4.0.13
+  - uses: pyiron/actions/cached-miniforge@main
     with:
       python-version: ${{ inputs.python-version }}
       env-files: ${{ inputs.standard-docs-env-file }} ${{ inputs.env-files }}
-  - uses: pyiron/actions/pyiron-config@actions-4.0.13
+  - uses: pyiron/actions/pyiron-config@main
   - name: Build sphinx documentation
     shell: bash -l {0}
     run: |
diff --git a/build-notebooks/action.yml b/build-notebooks/action.yml
index 2504ebf1..ae45028a 100644
--- a/build-notebooks/action.yml
+++ b/build-notebooks/action.yml
@@ -28,11 +28,11 @@ inputs:
 runs:
   using: 'composite'
   steps:
-  - uses: pyiron/actions/cached-miniforge@actions-4.0.13
+  - uses: pyiron/actions/cached-miniforge@main
     with:
       python-version: ${{ inputs.python-version }}
       env-files: ${{ inputs.standard-notebooks-env-file }} ${{ inputs.env-files }}
-  - uses: pyiron/actions/pyiron-config@actions-4.0.13
+  - uses: pyiron/actions/pyiron-config@main
   - name: Build notebooks
     shell: bash -l {0}
     run: $GITHUB_ACTION_PATH/../.support/build_notebooks.sh ${{ inputs.notebooks-dir }} ${{ inputs.exclusion-file }} ${{ inputs.kernel }}
diff --git a/cached-miniforge/action.yml b/cached-miniforge/action.yml
index b4b51760..1d176bbd 100644
--- a/cached-miniforge/action.yml
+++ b/cached-miniforge/action.yml
@@ -62,7 +62,7 @@ inputs:
 runs:
   using: "composite"
   steps:
-  - uses: pyiron/actions/write-environment@actions-4.0.13
+  - uses: pyiron/actions/write-environment@main
     with:
       env-files: ${{ inputs.env-files }}
   - name: Calculate cache label info
diff --git a/export-secret-env/action.yml b/export-secret-env/action.yml
new file mode 100644
index 00000000..ab664b37
--- /dev/null
+++ b/export-secret-env/action.yml
@@ -0,0 +1,18 @@
+name: 'Export selected secrets'
+description: 'Export selected GitHub Actions secrets to later steps as environment variables'
+
+inputs:
+  secret-env-map:
+    description: 'Newline-separated SECRET_NAME or ENV_NAME=SECRET_NAME entries'
+    default: ''
+    required: false
+
+runs:
+  using: 'composite'
+  steps:
+  - name: Export selected secret env vars
+    if: ${{ inputs.secret-env-map != '' }}
+    shell: bash -l {0}
+    env:
+      PYIRON_SECRET_ENV_MAP: ${{ inputs.secret-env-map }}
+    run: python "$GITHUB_ACTION_PATH/../.support/export_secret_env.py"
diff --git a/pip-check/action.yml b/pip-check/action.yml
index 3646304b..b94825bd 100644
--- a/pip-check/action.yml
+++ b/pip-check/action.yml
@@ -13,7 +13,7 @@ inputs:
 runs:
   using: 'composite'
   steps:
-  - uses: pyiron/actions/cached-miniforge@actions-4.0.13
+  - uses: pyiron/actions/cached-miniforge@main
     with:
       python-version: ${{ inputs.python-version }}
       env-files: ${{ inputs.env-files }}
diff --git a/unit-tests/action.yml b/unit-tests/action.yml
index 497d5c17..e98caa2c 100644
--- a/unit-tests/action.yml
+++ b/unit-tests/action.yml
@@ -72,11 +72,11 @@ runs:
       echo "ENV_FILES = ${ENV_FILES}"
       echo "env_files=$ENV_FILES" >> $GITHUB_OUTPUT
 
-  - uses: pyiron/actions/cached-miniforge@actions-4.0.13
+  - uses: pyiron/actions/cached-miniforge@main
     with:
       python-version: ${{ inputs.python-version }}
       env-files: ${{ steps.prepare-env-files.outputs.env_files }}
-  - uses: pyiron/actions/pyiron-config@actions-4.0.13
+  - uses: pyiron/actions/pyiron-config@main
   - name: Test
     shell: bash -l {0}
     run: |